Best absorbable monosaccharide
**Core Concept**
Glucose is the primary energy source for cells, and it is essential to understand the absorption and utilization of glucose in the human body. Glucose absorption occurs in the small intestine through a facilitated diffusion process facilitated by sodium-glucose cotransporters.
**Why the Correct Answer is Right**
Glucose is the most efficiently absorbed monosaccharide in the small intestine. The sodium-glucose cotransporter 1 (SGLT1) is responsible for glucose absorption, and it has a high affinity for glucose, allowing for rapid and efficient absorption. Glucose is then transported across the intestinal epithelial cells and into the bloodstream, where it can be utilized by cells throughout the body.
**Why Each Wrong Option is Incorrect**
**Option A:** Fructose is also an absorbable monosaccharide, but it is primarily absorbed in the proximal small intestine through a different transport mechanism.
**Option B:** Galactose is another monosaccharide, but it is not as efficiently absorbed as glucose and requires conversion to glucose before it can be utilized by cells.
**Option C:** Xylose is a pentose sugar and is not a typical absorbable monosaccharide in the small intestine.
**Clinical Pearl / High-Yield Fact**
Glucose absorption is essential for maintaining normal blood glucose levels, and impaired glucose absorption can lead to malabsorption and metabolic disorders.
**Correct Answer: D. Glucose.**